Why does my Samsung S5 battery drain do quickly?

I have read lots of threads. I have uninstalled that allshare dongle, amazon stuff, cleared the cashe, disabled location, sync, and a full 100% charge won't last the night when phone isn't being used. I have just done an update too. Is it time to take phone in for repair or swap? Its driving me nuts ! Only get 4-5 hours of usage during the day. I have even bought a new battery. The only thing i havnt done is a factory reset, and the only reason I've not done that is because of the hassle with re-entering contacts. Any other ideas?